Mine arch supports



Aug. 6, 1957 Q KUHN 2,801,522

MINE ARCH SUPPORTS Filed Feb. 25, 1953 2 Sheets-Sheet 1 Aug. 6, 1957 QKUHN 2,801,522

MINE ARCH SUPPORTS Filed Feb. 25, 195s 2 sheets-sheet 2 W a 21W UnitedStates Patent 2,801,522 MINE ARCH SUPPORTS Otto Kuhn, Essen-Bredeney,Germany, assigner to Deutsche Khlenbergbau-Leitung, Essen, GermanyApplication `l'iebruary 25, 1953, Serial N o. 338,799

Claims priority, application Germany February 28, 1952 `7 claims, (c1.s1-45) In carrying out the mechanisation of face roadways in mines, roofsupporting structures have been proposed which comprise two props whichare of adjustable length and a reef bar connecting these props, thelatter being arranged on a common sole piece or being interconnected bya cross bar above the sole. The roof bars used in these constructionshave the disadvantage that where the roof is uneven theyare only appliedagainst the roof over a small part of their length, for instance at theends only, and consequently 'are subjected to objectionable bendingstrains. This drawback vis also encountered in a roofsuppor for use atthe coal face, in which pivotally interconnected short .roof .bars areeach supported by a pit prop somewhere about midway along its length.

The invention is aimed at `overcoming this drawback, to which end itresides in a combination of the following features:

(a) The roof bar is composed of a plurality of sections (preferably two)which are hingedly interconnected at joints which permit a relativeangular adjustment of the jointed sections at least in the verticalplane.

(b) Each section of the roof bar is pivotally connected to a pit propwhich serves to support the same.

(c) The outer ends of the roof bar made up of the inter-coupled roof barsections are connected by a draw means which is located at the roof sideof the bar and which is supported against the bar sections by resilientmeans (particularly by springs).

Advantageously the props are equipped with supporting members (forexample head plates or laggings) which are located between the roof andthe roof bar sections, these members also preferably being used to pressthe draw means against the roof. In a preferred case, the draw meansitself consists of a steel strip, but other means can be employed, forexample a wire cable.

The individual features of the combination of this invention are per seknown, but the object of the invention is only met by a combination ofall these features, such combination producing a simple high1oadcapacity roof bar of small thickness which supports the roof over acomparatively extended length even where this is most uneven, whilst atthe same time undesirable bending strains are avoided.

Tightening devices, for example in the form of wedges or screws, can beassociated with the draw means. Moreover, the ends of such draw meanscan be detachably secured to the ends of the roof bar, e. g. by means ofpushed-on sleeves or the like, which enables roof bars which, inprinciple, are of known form, to be readily modified in accordance withthe proposal of this invention.

The invention is suited, with particular advantage, to the production ofan arch support for a mechanical face Working. A structural element ofthis character will then advantageously comprise two hingedlyinterconnected roof bar sections or parts each of which is supported bya prop, these props being connected together by a cross piece or thelike located close to the oor of the working. It is, however, to beunderstood that mine arches in accordance with this invention are alsocapable of use with advantage otherwise than in a mechanical faceworking. An embodiment of the arch support according to this inventionis illustrated in the accompanying drawmg.

Figure 1 is an elevational view of the arch structure mounted in a coalseam which has an even roof;

Figures 2 and 3 illustrate the same structure used in connection withroofs which are, respectively, of concave and `convex formation; and

Figures 4 and 5 are respectively a side elevation and a plan View, on alarger scalethan that of Figures 1 to 3, of the connection between theprop, roof bar and draw means of the structure of Figures 1 to 3.

In the embodiment illustrated, the arch support consists `of pit props 1and 2 which are interconnected by a cross bar 14 near the floor andserve to support the roof bar Vwhich is made up of two sections 3 and 4respectively pivoted Vto the props 1 and 2 at 5 and 6. The sections 3and 4 are interconnected at `their adjacent ends by a hinged joint '7.Head plates 8 and 9 are pivotally connectedat the top of the props 1 and2 respectively. The outer `ends of the roof bar sections 3 and 4 areconnected by a steel strip 10 which is passed over the upper sides ofthe head :plates "8 and 9. Upstanding projections 13 may `be1provided atthe outer ends of the sections 3 and 4 for connection of the strip ends,or these ends may be detachably secured to therespective ends of thesections, for example by sleeves 13a which releasably engage the ends ofthe roof bar sections as shown in Figures 4 and 5.

Thus as shown in Figures 4 and 5, the strip 10 terminates in a loop 10awhich embraces one limb of a shackle 15 the other limb of which isformed with an extension 16 which passes through a central boss in across-head form sleeve 13a, the limbs of which are adapted releasably toengage the end of the roof bar section 4; the latter, as clearly shownin Figure 5, comprises a pair of parallel beams disposed one on eachside of the prop 2. The extension 16 is slotted to accommodate a wedge17 which may be driven into the slot to effect tensioning of the strip10.

Springs 11 and 12 are disposed between the strip 10 and the upper faceof the two roof bar sections. It will be understood that more springsthan are actually here illustrated can be employed, this multiplicity ofsprings being distributed over the length of the roof bar.Advantageously the springs 11 and 12, where only these two are employed,are arranged in the vicinity of the joint 7. As can be seen from Figure2, the springs prevent the hinged connecting joint 7 between the roofbar sections from being pressed upwards to an excessive extent.

To enhance the elasticity of the roof bar, and thus its capacity toconform to the roof, it is of advantage to make the sections 3 and 4 ofa material having a small modulus of elasticity but a high elasticlimit, for example of an improved aluminium alloy of the Al-Cu-Mg type.

I claim:

l. A mine roof support, comprising: a roof bar composed of a pluralityof sections hingedly jointed end-toend for relative angular adjustmentin a vertical plane, a pit prop for pivotally supporting each of saidroof bar sections, a draw means interconnecting the outer ends of thecomposite roof bar and disposed at the roof side of the bar, compressionsprings disposed between said roof bar and draw means at least in theregion of the hinged connection between the adjacent roof bar sections,and a supporting member pivotally mounted at the upper end of each propbetween the roof bar sections and the draw means and serving to pressthe draw means against the roof.

2. A mine roof support according to claim 1, in which the draw means isa steel strip.

3. A mine roof support, comprising: a roof bar composed of a pluralityof sections hingedly jointedend-toend for relative angular adjustment ina vertical plane, a pit propifor pivotally supporting each of said roofbar sections, a draw means interconnecting the outer ends of thecomposite roof bar and disposed at the roof side of said bar,compression springs disposed between said roof bar and draw means in theregion of the hinged connection between the adjacent roof bar sections,a supporting member on the end of each pit prop and in Contact with thedraw means, and tightening means for said draw means.

4. A mine roof support according to claim 1, in which each section ispivotally mounted on the upper end of its pit prop approximately at theImid-point of theV section.

5. A mine roof support according to claim l, in which the pair ofsections include two pairs arranged parallel to each other one on eachside of the pit prop.

6. A mine roof support, comprising: a roof bar cornposed of a pluralityof sections hingedly jointed end-toend for relative angular adjustmentin a vertical plane, a pit prop for pivotally supporting each of saidroof bar sections, a draw means interconnecting the outer ends of thecomposite roof bar and disposed at the roof side of the bar, compressionsprings disposed between said roof bar and draw means at least in theregion of the hinged connection between the adjacent roof bar sections,a supporting member pivotally mounted at the upper end of each propbetween the roof bar sections and the draw CII means and serving topress the draw means against the roof, and a cross bar connected to thepit props near the bottom ends thereof to form a closed frame relativeto the roof bar and the pit props.

7. A mine roof support, comprising: a roof bar composed of a pluralityof sections hingedly jointed end-toend for relative angular adjustmentin a vertical plane, a pit prop for pivotally supporting each of saidroof bar sections, a draw means interconnecting the outer ends of thecomposite roof bar and disposed at the roof side of said bar,compression springs disposed between said roof bar and draw means in theregion of the hinged connection between the adjacent roof bar sections,`a supporting member on the end of each pit prop and in Contact with thedraw means, tightening means for said draw means, and a cross barconnected to the pit props near the bottom ends thereof to form a closedframe relative to the roof bar and the pit props as an approximaterectangular configuration.

References Cited in the file of this patent UNITED STATES PATENTS2,650,475 Gerlach Sept. 1, 1953 2,714,505 Joy Aug. 2, 1955 FOREIGNPATENTS 891,261 France of 1943 961,322 France of 1949 805,635 GermanyMay 25, 1951

